The proposed research is aimed at increasing knowledge concerning the psychological, social, and biological responses of rescue workers who participated in the I-880 freeway collapse rescue mission after the 1989 Bay Area earthquake. The proposal addresses the following issues: the time-course and dimensions of stress response; the role of dissociation and other risk factors in explaining outcome, the role of control expectancies, threat appraisal, and coping strategies on outcome, the impact of debriefing on outcome; the ability of psychophysiological and neuroendocrine measures to differentiate high from low stress responders following stress re-exposure; and the interrelationship among multiple dimensions of stress response. To accomplish these aims, two studies are proposed. In Study 1, three groups will be surveyed. The high exposure group consists of 250 I-880 rescue workers in police, fire, ambulance, private construction, and state highway construction positions. Two control groups with lower exposure, drawn from the same five occupations, are proposed. The Bay Area control group consists of 150 subjects, who experienced the earthquake but did not participate in the I-880 or other major earthquake rescue operation. The San Diego control group consists of 150 rescue workers who did not experience either the earthquake or a major recent disaster operation. A battery of self-report questionnaires will be administered to all three groups, with diagnostic interviews for high stress responders and selected low stress responders who had high stressor exposure. In Study 2, three groups of 25 will be selected from study 1, for intensive psychobiological and behavioral study. The first and second groups will be I-880 workers with high stressor exposure, half with high stress response and half with low stress response. The third group will be selected from the Bay Area controls. All will receive diagnostic interviews and behavioral assessments. Psychophysiological and neuroendocrine assessment will be done before and after viewing a videotape of the I-880 disaster.